The present invention relates to optical scanners, and more specifically to micromachined semiconductor optical scanner.
An optical scanner having a rotatable mirror to direct reflected light to a desired direction is widely used in bar code reader, laser beam printer, display, and laser radar for a vehicle. In addition to a conventional optical scanner having a motor for driving a mirror, there has been proposed recently a micromachined semiconductor or crystal optical scanner that is superior in miniaturization and speed.
A published Japanese Patent Application, Publication (Kokai) No. 9-54264 discloses such a micromachined semiconductor optical scanning apparatus.
It is an object of the present invention to provide a small-sized reliable optical scanning apparatus simple in construction yet accurate in measurement.
According to the present invention, an optical scanning apparatus comprises: a mirror reflecting a light beam; a frame; a beam extending from the frame to the mirror and supporting the mirror to form a vibrating structure vibrating in bending mode and twisting mode to scan the light beam reflected from the mirror two-dimensionally; an actuator to excite the vibrating structure of the mirror and the beam in the bending mode and twisting mode; and a strain sensing section comprising a sensing element group arranged to sense bending deformation of the beam and to sense twisting deformation of the beam. The sensing element group comprises first and second longitudinal elements which extend longitudinally of the beam from the frame toward the mirror, and which are arranged to sense the twisting deformation of the beam with a difference between outputs of the first and second longitudinal elements.
According to the present invention, a fabricating process for fabricating a scanner substrate, comprising: forming a sensing section in a first major surface of a semiconductor substrate; forming a mirror film above the first major surface of the semiconductor substrate; and etching the semiconductor substrate selectively to form a mirror comprising the mirror film, a frame and a beam extending from the frame to the mirror and supporting the mirror.
The other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.